|Year|Chassis|Engine|Start|Finish|
|---|---|---|---|---|
|1974|Eagle|Offy|21st|7th|
|1975|Eagle|Offy|18th|4th|
|1976|Eagle|Offy|6th|5th|
|1977|Eagle|Offy|8th|15th|
|1978|Lighning|Cosworth|21st|24th|
|1979|Lighning|Cosworth|17th|20th|
|1980|Penske|Cosworth|8th|6th|
|1981|Penske|Cosworth|10th|28th|
|1982|March|Cosworth|10th|3rd|
|1983|March|Cosworth|14th|7th|
|1984|March|Cosworth|21st|19th|
|1985|March|Buick|1st|33rd|
|1986|Lola|Cosworth|14th|16th|
|1987|March|Cosworth|29th|27th|
|1988|March|Buick|Qualifying Crash||
|1989|Lola|Cosworth|32nd|22nd|
|1990|Lola|Cosworth|22nd|29th|
|1991|Lola|Buick|32nd|21st|
|1992|Lola|Buick|Failed to Qualify||
|1994|Lola|Chevrolet|Failed to Qualify||

Question: how many consecutive years are listed?
Answer: 20